Excessive scaring resulting from the healing of wounds can present a significant aesthetic and functional problem for patients after surgery or traumatic injury to the skin. Excessive scars are generally classified as hypertrophic scars or keloids. While these scars differ in appearance, they are the result of similar processes whereby skin and connective tissue cells deposit more tissue than is necessary to repair the wound. The deposition of excess tissue may continue for months and even years after the initial skin trauma and can in extreme cases, adversely affect the range of motion of joints. These scars are problematic because they can be painful, generate unpleasant itching or burning sensations, may be unsightly such as by differing in color from surrounding tissue, and may limit joint mobility when they occur in the skin around a joint. The strength of skin affected by scar formation may also be reduced. Skin lacking normal strength is susceptible to re-laceration of the tissue and thus further scarring. While there are topical creams, bandages, injections, and surgeries that may bring some reduction in the appearance of these scars, there is no reliable therapy for the prevention of scar formation or treatment for existing scars currently available. Therefore, it is desirable to have a mode of therapy to prevent scar formation and to reliably reduce the appearance and functional impact of severe scars including hypertrophic and keloid scars.
One approach taken by the prior art to treat wounds and/or scars is to pass an applied current (i.e alternative or direct current) into the body where the wound or scar forms part of the primary electrical circuit. However, such systems are disadvantageous because: 1—applying an applied current to the body may pose a risk to patients with cardiac assistive devices such as pacemakers and defibrillators; 2—applying an applied current to the body can impact medical instruments used to monitor patients under medical supervision, such as, EKG and EEG; 3—applying an applied current may damage (burn) tissues of the body if arching occurs or if the applied current exceeds safe levels; 4—applying an applied current in close proximity to a nerve can cause unwanted muscle activity and/or pain; and 5—the maximum applied current that can be applied safely to avoid the aforementioned complications has not been adequately studied.
One effort to minimize the deleterious effects of an applied current is the use of static electricity. Bernard Hirshowitz et al. Plastic Reconstr. Surg., Vol. 101 (5) April 1998 disclose a bandage for treatment of hypertrophic and keloid scars using silicone cushions which, upon actuation by exerting pressure with the fingers, generates negative static electricity in which “the interaction between the negatively charged ions of the cushion and the ionic charges of the tissue fluids may be the critical factor in achieving hypertrophic and keloid scar involution”. Nonetheless, the reference system employs an applied current which remains problematic.
There have been efforts to treat wounds and scars without using an applied current. One treatment for scar tissue that has received attention in the medical literature without using an applied current makes use of silicone occlusive bandages. Alexandrina S. Saulis (Aesthetic Surg. J. Vol. 22, Issue 2, pp. 147-153 (2002) disclose a reduction in the severity of scars when silicone occlusive bandages are used in animal models during the healing process.
For wound healing, it was observed from U.S. Pat. No. 4,142,521 that weak electrostatic fields provided by electret-type devices within a wafer thin disposable bandage could enhance the healing process. Electret materials, as described in the reference, are permanently polarized pieces of dielectric materials which may be made by subjecting a dielectric material to a strong electric potential difference. Elisa Burgess et al., Plastic Reconstr. Surg., Vol. 102(7) December 1998 disclose that positively charged cross-linked diethylaminoethyl dextran beads could significantly enhance the tensile properties of healing wounds. The electrostatic charge contained in the active materials used in the prior art serves to polarize the soft tissue of the wound or scar and it is this polarization which appears to contribute to wound and scar healing.
The systems employed in the prior art described above which have avoided the use of an applied current have limitations because the electrostatic charge associated with these systems and particularly electret materials are of limited intensity and it is believed that a greater intensity of the electrostatic field is needed to achieve adequate wound and/or scar healing.
Accordingly, Applicants have developed a device in the form of a bandage capable of generating an electrostatic field at the site of a wound and/or scar in which the intensity of the electrostatic field can be varied according to the particular wound and/or scar to be treated. The intensity of the electrostatic field can exceed that associated with electret materials and therefore obtain a beneficial healing effect without the use of an applied current. The present device also provides the ability to alter the polarity of the induced electrostatic field which may likewise positively impact wound and/or scar treatment.